Before the era of Big Brother, censorship was alive and well. LiveScience
explained how two censors took about their work in making sure that work
critical of the church by Dutch Renaissance humanist Erasmus
never saw the light of day:

In contrast to the newly discovered glued-up book, another example
of Erasmus' writing, held at the Centre for Renaissance and Reformation
Studies at the University of Toronto, reveals a censor who took to his
task with an artistic flourish.

Published in Basel, Switzerland, in 1538 this book contains essays
by Erasmus introducing the writing of St. Ambrose, a fourth-century
saint who was the bishop of Milan.

"It is one of the most exquisitely beautiful examples of censorship,
with the offending passages obliterated using vibrant watercolors framed
in baroque scroll frames with attending putti (an image of a male child),"
Carefoote writes in his 2007 book. While the censor blanked out the
prefaces by Erasmus he left the saint’s work alone. It's not known
what Erasmus said that got him censored.It's also not known why the
censor, probably a librarian, approached his job with such artistry.